P2G-1 Effect of Nonuniform Loading Layer on Monolithic Thickness-Mode Piezoelectric Filters

The effect of using a nonuniform loading layer on the frequency response of a thickness-mode piezoelectric filter is investigated. The goal is to create multiple peak frequency shifts by one extra loading layer on the filter structure. By varying the area of the loading layer, not only the peak frequency is shifted but also extra bandpass filters are created at an offset from the original filter. This may enable the fabrication of compact filter arrays for multi-channel systems. Preliminary measurement results show up to 300 MHz frequency shift for acoustically coupled piezoelectric-on-substrate filters operating at 1.2-1.5 GHz.